In a small mixing bowl pour enough boiling water over dried cherries to cover. Let stand for 5 minutes; drain well. In large mixing bowl combine flour, brown sugar, baking powder, salt, and baking soda. Using a pastry blender, cut in butter until mixture resembles coarse crumbs. Add drained cherries and orange peel; toss to coat. Make a well in the center; set aside.
In a small mixing bowl combine egg yolk and sour cream. Add egg mixture all at once to dry mixture. Using a fork, stir until combined (mixture may seem dry).
Turn dough out onto a lightly floured surface. Quickly knead dough by folding and gently pressing for 10 to 12 strokes or until dough is nearly smooth. Pat or lightly roll dough into a 7-inch circle. Cut into 12 wedges.
Arrange wedges 1 inch apart on an ungreased baking sheet. Bake in a 400 degree F oven for 10 to 12 minutes or until light brown. Cool on a wire rack for 10 minutes.
In small bowl stir together powdered sugar, orange juice, and vanilla. Stir in enough additional orange juice, 1 teaspoon at a time, to make of drizzling consistency. Drizzle over warm scones. Serve immediately. Makes 12 servings.